Location
Suwanee, GA
Start Date
6-5-2025 1:00 PM
End Date
6-5-2025 4:00 PM
Description
Smooth, goal-directed reaching movements require precise motor coordination, a function often impaired in cerebellar ataxia. Distinguishing between normal and ataxic movement requires a measure of smoothness of movement. Previously a linear smoothness index was developed, which relied on deviations from linear trajectories and acceleration profiles of reaching movement in the mouse forelimb. This linear smoothness index approach may not accurately capture the natural movement patterns of this reaching motion in the mouse model due to the more natural curve the mouse exhibits in this movement. In this project, a new index was introduced by incorporating a curved path, developed from prior work demonstrating the utility of curved path models in modeling human hand trajectories. This curve incorporated the reach patterns of multiple reaching movements to offer a flexible representation of movement that accounts for natural kinematic variability. The goal was to compare the new index of smoothness to the linear model to find if the curved model provides a higher level of discrimination between normal and ataxic movement.
This revised metric was applied to analyze reaching behavior in normal and transgenic mice (n=8). Mice were head-plated and placed on water restriction for at least two days preceding training for reaching behavior. They were head-fixed on a mount and trained to reach for water drops dispensed from a needle approximately 1 mm from the snout. Reaching movements were tracked using DeepLabCut, with trajectory data collected and analyzed in MATLAB. All reaches were averaged into a reference trajectory or averaged curve against which deviations were measured. Electrophysiological recordings from the ventromedial thalamus were obtained simultaneously to assess neural correlates of reaching behavior. Previous linear-derived smoothness index study compared smoothness indices between ataxic and normal mice using an unpaired t-test with 78 trials and possessed a p-value of 0.0275. Preliminary results using the newer curve-based smoothness index with 61 trials possessed a p-value of 0.0148, indicating a more significant degree of difference between the two indices and potentially suggesting a more definitive standard for determining smoothness.
These findings demonstrate the relevance of curved path models in analyzing fine motor impairments in a preclinical setting. Refining smoothness metrics with a curved path model may provide a more physiologically accurate measure of motor impairment in ataxic models. Future studies will further validate this approach and explore its implications for assessing and potentially modulating cerebellar motor control in combination with thalamic electrophysiology recordings.
Embargo Period
5-28-2025
Included in
Refining the smoothness index for reaching in ataxic mice using a curved model
Suwanee, GA
Smooth, goal-directed reaching movements require precise motor coordination, a function often impaired in cerebellar ataxia. Distinguishing between normal and ataxic movement requires a measure of smoothness of movement. Previously a linear smoothness index was developed, which relied on deviations from linear trajectories and acceleration profiles of reaching movement in the mouse forelimb. This linear smoothness index approach may not accurately capture the natural movement patterns of this reaching motion in the mouse model due to the more natural curve the mouse exhibits in this movement. In this project, a new index was introduced by incorporating a curved path, developed from prior work demonstrating the utility of curved path models in modeling human hand trajectories. This curve incorporated the reach patterns of multiple reaching movements to offer a flexible representation of movement that accounts for natural kinematic variability. The goal was to compare the new index of smoothness to the linear model to find if the curved model provides a higher level of discrimination between normal and ataxic movement.
This revised metric was applied to analyze reaching behavior in normal and transgenic mice (n=8). Mice were head-plated and placed on water restriction for at least two days preceding training for reaching behavior. They were head-fixed on a mount and trained to reach for water drops dispensed from a needle approximately 1 mm from the snout. Reaching movements were tracked using DeepLabCut, with trajectory data collected and analyzed in MATLAB. All reaches were averaged into a reference trajectory or averaged curve against which deviations were measured. Electrophysiological recordings from the ventromedial thalamus were obtained simultaneously to assess neural correlates of reaching behavior. Previous linear-derived smoothness index study compared smoothness indices between ataxic and normal mice using an unpaired t-test with 78 trials and possessed a p-value of 0.0275. Preliminary results using the newer curve-based smoothness index with 61 trials possessed a p-value of 0.0148, indicating a more significant degree of difference between the two indices and potentially suggesting a more definitive standard for determining smoothness.
These findings demonstrate the relevance of curved path models in analyzing fine motor impairments in a preclinical setting. Refining smoothness metrics with a curved path model may provide a more physiologically accurate measure of motor impairment in ataxic models. Future studies will further validate this approach and explore its implications for assessing and potentially modulating cerebellar motor control in combination with thalamic electrophysiology recordings.